Memory devices are typically provided as internal, semiconductor, integrated circuit devices in computers or other electronic devices. There are many different types of memory including random-access memory (RAM), read only memory (ROM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), and flash memory.
Flash memory devices have developed into a popular source of non-volatile memory for a wide range of electronic applications. Flash memory devices typically use a one-transistor memory cell that allows for high memory densities, high reliability, and low power consumption. Changes in threshold voltage of the memory cells, through programming (which is often referred to as writing) of charge storage structures (e.g., floating gates or charge traps) or other physical phenomena (e.g., phase change or polarization), determine the data value of each cell. Common uses for flash memory include personal computers, tablet computers, digital cameras, digital media players, cellular telephones, solid state drives and removable memory modules, and the uses are growing.
A comparator may be used to compare a test signal to a reference signal in an integrated circuit, such as a memory device. An integrated circuit may include multiple comparators to compare multiple test signals to a reference signal or to multiple reference signals. Multiple comparators within an integrated circuit, however, may result in a large constant current draw and may also occupy a significant amount of space within the integrated circuit. The constant current draw and the area occupied by the comparators in an integrated circuit should be minimized to improve efficiency and lower cost.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for alternative methods for comparing multiple test signals to a reference signal, and system and apparatus to perform such methods.